Sight string



W. L. WILLIS May 5, 1953 SIGHT STRING Filed Jan. 8, 1951 36 u n I 40 WII/Iam Lee Wl/l/S INVENTOR.

BY @g w 2,,

Patented May 5, 1953 UNITED STATES PATENT OFFICE SIGHT STRING William Lee Willis, Pruden, Tenn.

Application January 8, 1951, Serial No. 204,995

2 Claims.

cylindrical casing in which is wound a flexible tape, or string for supporting the target, and which flexible cable is controlled by a releasable ratchet and spring means within the target.

In mining operations it is important that the tunnels or drifts be extended in a straight line and to accomplish this end two plumb lines carrying sighting targets are suspended from the ceiling of the tunnel or drift near its entrance and when it is desired to determine the direction of the tunnel by the miner, it is only necessary for him to sight back at the entrance of the tunnel and align a sighting target, which may be suspended from the ceiling of the tunnel adjacent where he is working and move the same into proper alignment with the plumb line targets near the entrance of the tunnel. Conventional sighting targets which have been used and comprising a ring of metal carried on a string having hooks on the outer ends of the string for fastening the same to the wall or ceiling of the tunnel have been inconvenient to use because of the tendency of the string and hooks to become entangled so that much time is wasted in preparing the targets for use. The present invention overcomes these difiiculties and provides a novel and readily operable sighting target.

These, together with various ancillary objects, features and advantages of this invention, which will later become more apparent as the following description proceeds, are attained in the present invention, a preferred embodiment of which has been illustrated, by way of example only, in the accompanying drawings wherein:

Figure 1 is a sighting target constructed in accordance with the present invention and shown supported in sighting position from the ceiling of a tunnel;

Figure 2 shows the sighting target illustrated in Figure 1 on a somewhat larger scale and wherein the supporting strings are retracted and enclosed in the target;

Figure 3 is a fragmentary detail sectional view on an enlarged scale illustrating the manner of attaching the strap to the string or supporting cord member for the target;

Figure 4 is a plan view of the target with the cover removed and showing the outer casing portion in section; and

Figure 5 is a cross sectional view taken on the line 5-5 of Figure 4 and looking in the direction of the arrows.

Referring now more particularly to the drawings, wherein like reference characters refer to like parts throughout the several views, the numeral 10 indicates generally a sighting target constructed in accordance with this invention and which comprises a cylindrical housing or casing 12. The cylindrical casing I2 is provided with a complementary cylindrical cover member I4 which is suitably fitted thereon and retained by cap screw It. This cap screw is threaded onto the end of an internally threaded sleeve 18 which extends centrally through the casing l2 and housing I l, being suitably secured to the casing [2 by means of a nut 20 threaded on the outer end adjacent the housing, as shown in Figure 5.

Arranged within the casing i2 and suitably journaled on the sleeve i8 is an open-ended drum 22 in which is coiled a motor spirng 24, the inner end of the spring being secured to the sleeve l8 and the outer end to the drum 22, as by means of a rivet 26. The drum 22 preferably is made of a lightweight material such as a moldable plastic resin or lightweight metal, and has mounted on one end a disk 23 having a central aperture for receiving the sleeve Hi, the disk 28 being provided with a clutch element comprising a central boss 32 which is provided with notches 34 which are diametrically disposed therearound. For fixedly securing the disk member 28 to the drum 22, a retaining ring member 36 is secured to the face of the drum 22 as by means of the cap screws 40.

The drum 22 comprises a U-shaped periphery for receiving a cord or string 44 for supporting the target l2, and which string is arrange to be wound around the periphery of the drum as illustrated in Figure 5. The string idis arranged to pass through a looped strap 46 which is suitably fastened to the periphery of the drum, as by being passed around a portion of the hollow drum, as at 48, being arranged to pass through the apertures 50 provided in the face of the drum as illustrated in Figure 3.

The outer ends of the string 44 are provided with hooks 54 which are arranged to engage in the eye portion 58 of a pin 58 which is adapted to be driven into the ceiling of a tunnel, a portion of which is shown at 60 in Figure 1.

For locking the spring 24 so as to prevent its being operated to rewind the string 44 and strap 46 on the drum 22, a pin or plunger 64 is arranged within the sleeve 18 and which is provided with a substantially fiat spring providing laterally extending arms 68 on the inner end, the arms 66 being movable vertically relative to the sleeve 18 through the vertically disposed slots 68 in the sleeve l8. A coil spring 68 is arranged in the sleeve (8 and is arranged to abut against the innenend of thecap screwlfi and impinge against the inner-end of the pin 64 to urge it outwardly so as to engage the arms 65 in the notches 34 in the clutch element 32.

Thus, by.

pressing the pin 64 inwardly, the arms 66 are released from the notches 3 1 so as to permit' the operationand advantages of the invention will be readily understood by thoseskilled in the art."

Minor changes; omissions and: substitutions may be madein' the details of construction illustrated and dscribe'd,'- and such as isunderstood to fall within thescope 'of the invention as' particularly pointed out i in the appended claims.

Having described 'ithe inve'ntion, what is 1. A sighting target comprisinga casing, a drum rotatable in said casing, a. flexible loop connected'to said drum and-windable thereon, a

suspension string slidable through the loop, means on the ends of the suspension string for securing same to a support, and means for actuating the drum for winding the loop and the suspension string thereon.

2. A sighting target comprising a cylindrical casing, a sleeve extending centrally through the casing-and having longitudinal slots in one end portion, alheaded' retaining'screw threaded into the slotted end portion of the sleeve, a retaining nut threaded on the other end portion of said sleeve, a drum rotatable 0n the sleeve, a suspension string connected to said drum for windin thereon, a string connected to the drum for actuating'same'for Winding the string, a disk on one end of the drum, a retaining ring for said disk on said one end of said drum, a notched clutch element on the disk, a plunger slidable in the sleeve and projecting from said other end thereof for'm'an'ual actuation in one direction, a substantially flat spring on the plunger operable in the-slots and engageable With the clutch element for releasably se'curinigthe drur'ri against rotation by the first named spring, and a coil spring the sleevebetween the screw and the plunger for actuating said plunger in the opposite direction for engaging the second named spring with the clutch element.

WIIJLIAM'LEE WILLIS.

References Cited in thefile of this patent- UNITED STATES'P ATENTS Number Name Date 996,475 Fitton et al June 27', 1911 1,043,943 7 Krulan et al. Nov. 12, 1912 1,415,489 Simpson May 9, 1922 1,814,484 Morris July 14, 1931 

